1. Field of the Invention
The present invention relates to a temporary storage device and a temporary storage method for temporarily storing articles between a plurality of transport systems, and a transport system using the temporary storage device.
2. Description of the Related Art
In semiconductor factories, cassettes housing semiconductor wafers are transported by an overhead travelling vehicle system between load ports of processing devices. The applicant has proposed providing, as a temporary storage device between an overhead travelling vehicle system and a load port, a local carrier, travel rails of the local carrier, and a buffer, between the load port and a travel rail of the overhead travelling vehicle (See, for example, JP 5229363 B2). In this device, a cassette can vertically pass between the travel rails of the local carrier, and the buffer is provided below the travel rails of the local carrier so that the overhead travelling vehicle and the local carrier can both access the buffer. Therefore, the overhead travelling vehicle and the local carrier can both access the load port and the buffer.
Passing is sometimes required during transport. For example, it may be desired that a cassette containing express articles (a hot lot) is transported so as to pass a cassette containing normal articles. For this purpose, a transport system for hot lots may be provided in addition to a transport system for normal articles. However, it is further required that the transport system for normal articles and the transport system for hot lots can be connected to the same article transfer position.